Train-describing system



Mail-ch 3, 1931. AJLANGDON TRAIN DESCRIBING SYSTEM Filed Jan. 19, 1929INVENTOR Patented Mar. 3, 1931 UNITED STATES PATENT OFFICE ANDREWLANGDON,'OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNALCOMPANY, OF ROCHESTER, NEW YORK TRAIN -DESCRIBI1\TG SYSTEM Applicationfiled January 19, 1929. Serial no. 333,658.

This invention relates to apparatus for indicating at a particular pointon a railway system how many trains are approaching in an approachsection and in what order trains interlocking territory. Similarly, inrailway passenger stations of large size it is important that the traincaller be informed of A what train is approaching, so that he may callthe approach and departure of such train y In iew of the foregoing andother important considera'lions, it is proposed to provide a largenumber of indicators arranged in series of vertical rows, in which thelocation of the indicator in a row indicates the order of the train, andthe particular row itself indicates the class of the train, to providesuitable means controlled from a distanttower, over a comparatively fewline wires, suitable for controlling these indicators, to provide meansassociated with said indicators for transferring an indication from oneseries of indicators to the next proceeding series of indicators, in theevent that the indication of the proceeding series is cancelled becausea the train which it represented has already entered the interlockingyard. Other.characteristic features of the presentinvenion reside in theprovision of: audible signalling means at the interlocking tower soundedeach time that a train enters the approach zone.

in response to manual manifestation of such entrance of the train by anoperator at said distant tower, an audible signal means at said distanttower sounded each time that the interlocking operator in said distanttower, together with means for discontinuin such audible signal bymanual acknowle gment manifesting that the operator has observed achange in the signal indication. Another characteristic feature of thepresent inventlon resldes in the provision of automatic means forcancelling a particular indication and for transferring the indicationsin each of the successive indicating banks to the next proceedingindicating bank.

Other objects, purposes and characteristic features of the inventionwill in part be apparent from the accompanying drawing and willin partbe more fully described in the specification hereinafter.

In describing the invention in detail referencewill be made to thesingle accompany- 1ng drawing illustrating an embodiment of theinvention including signals, various devices, and the circuitarrangement in which they are connected.

Referring'to the drawing, the invention has been shown applied to theeast bound track of a double track railroad entering an interlockingplant. The entrance to the interlocking plant is defined by the locationof the main signal S and the diverging route signal S, the next signalin the rear being designated S and the second signal in the rear beingdesignated S This railway track system has been shown divided into tracksections by insulating joints 2.

The interlocking plant shown to the right of the signals S and S ispreferably controlled from a suitable interlocking tower, which towerhas been conventionally illustrated by the dotted rectangle T In theinterlocking tower shown, a large number of vertically arranged banks ofindicators are provided, of which for convenience only two banks havebeen shown, designated A and B respectively, and each of these bankspreferably contain suflicient indicators to indicate all of'theapproaching trains in the approach section between the signal S andthesignal S which in practice may requirev as many as 6 or 7 indicators, ofwhich only the trated. The interlocking tower apparatus also includes agroup of class and order relays A A A B B B in which the letter of thereference character designates the class of a train that a given relayrepresents, and the exponent of thisreference character designates theorder in which such train is approaching with respect to other trains.This same theory of designation has also been carried into the referencecharacters of the lamps. This interlocking tower apparatus also includesrouting relays R R R a lever L, a track relay T, a signal repeatingrelay IZR, a bell G the emergency release ush button ER, theacknowledging push button ACK, the audible indication stick rBe llay K,and the source of energy, battery Referring now to the extreme left handpart of the drawing illustrating the tower T this tower includes a pushbutton PA, push button PB, cancelling push button CB, an audible signalG a visual signal I, a stick relay XR, and the source of energy, batteryBT It is believed that the system in question is most readily understoodby considering the operation of the system.

OPERATION N ormal conditions With no trains in the approach sectionunder the supervision of this train describing indication system, thecondition of the circuits and control apparatus is virtually as shown inthe accompanying drawing. The routing relays R R and R must be energizedso that the control wires from the tower T shall be routed to the classrelays of the first order. mally energized and their circuits will-nowbe considered.

Circuit for R begins with positive battery at BTflthrough wires 4, 56,60, 66, back contact 25, wire 67, back contact 21, wire 68, throughrelay R to the common wire 3, back to negative of battery BT Circuit forR begins with positive battery at BTflthrough wires 4, 56, 60, 62,-backcontact 33, wire 64, back contact 29, wire 65,

' through relay R to the common wire 3, back to negative battery of BTCircuit for R begins with positive battery at BT", through wires 4, 5,6, 7, back contact 37, wire 8, back contact 35, wire 9, through relay Rto the common wire 3 back to nega tive battery BT It will be noted herethat the common negative wire extends from the battery BT to battery BThence circuits will be traced fromeither positive battery BT or BTthrough to the common wire only.

The track relay T is energized by its own track battery and is really apart of the standard signal system. v

These routing relays are nor-- First train in order-a Glass A train ingto that class. As the indication system is so designed that it willindicate as many trains as the supervised approach section may containat any one time, the operator has to register the class only, which inthis case is class A, which he registers on push button PA. Pressure onpush button PA closes contact 53, so that positive current flows frombattery BT through wires 84, 85, 86, contact 53, wire 82, front-contact10, wires 87, 88, front contact 12, wires 89, 90, front contact 15, wire91, through relay A to common wire 3, thus picking up the relay A Withrelay A in its attracted position a stick circuit to connect positivecurrent to said relay A is completed as follows :from battery 'BTthrough wires 4 and 97, back contact 42, wires 96, and 95, contact 52,wire 94, wire 93, front contact 18, wire 92, through relay A to commonwire 3. With relay A energized, there is a circuit made through frontcontact 19, which connects positive current to the lamp AL as follows:from battery BT through wires 4, 56, 60, 61 and 70, front contact 19,wire 71, through lamp AL to common wire 3. i

With relay A energized there is also a circuit made through frontcontact 20, which allows positive current to flow to the relay K asfOlIOWSf-fI'OIIl battery BT through wires 4, 56, 60, 61, 63, backcontact 28, wire 116, front contact 20, wire 100, front contact 17, wire101, front contact 14, wire 74, through relay -K to common wire Sfithusenergizing relay K. With relay K in its attracted position it closes itsstick circuit through front contact 38 by obtaining positive currentfrom battery BT through wires 4, 56, 57, 58, contact 51, wire 102, frontcontact 38, through relay K to common wire 3.

The front contact 39 of relay K thus closes the following circuit forbell G :from battery BT through wires 4, 56, 57, 59, bell G wire 103,front contact 39, to the common wire 3, thus causing bell G to ring andcalling the attention of the operator of inter 1 locking tower T to theindication given by lamp AL The operator at tower T now acknowledges theindication by depressing push buttons ACK, which breaks the stickcircuit of relay K by opening normally closed contacts 51. Depression ofthis push button ACK also closes the normally open contacts 51, thusenergizing the relay XR in tower T through I the following circuit :frombattery ET the circuit of bell G which ceases to ring. The momentaryenergization of relay XR picks it up, thus closing its stick circuit asfollows :from the battery BT through the wires 84, 85, 86 and 109,normally closed contact 55, wire 108,'front contact 45, wires 7 ing thebell and lighting the lamp in multiple therewith throughthe wires 84,'85, the lamp I, wire 107, front contact 46 to the common wire 3. Hence,as soon as the operatorin tower T recognizes that the operator in towerT has acknowledged the indication given by indicator AL he depressespush button CB, which opens the stick circuit of the relay XR, drops thecontacts and 46, and causes the indications of bell Gr andlamp I tocease.

. The energization of relay A by the depression of push button PA asheretofore explained, also caused back contact 21 to open the energizingcircuit of the relay R This causes the back contacts of relay R to routethe control wires to the class A and B so that as the first train inorder accepts the signal S or even before then, a second train in orderwhich is accepting the signal S may be indicated at the tower Tby'manual operation of one of the push buttons PA' or PB at the tower Tdepending upon the class of the next train as presently pointed out.

Second train in ordeM Glass B train When the operator notes that thesecond lows :'from the battery BT through the d wires 84 and 85,normally open contact 54, wire 83, front contact 11, wires 110, and 111,

, frontcontact 13, wire 112 and 113, back contact 16, wire 14, throughthe relay B to the common wire 3. This causesthe relay B to be energizedthrough its stick circuit, as soon as it picks up, the stick circuitcomprising starting from the battery BT, through the wires 4, 56, 60,and 62, front contact 30, wires 79, 113, backcontact 16, wire 114,through the relay B to the common wire 3. With the relay B held upthrough its stick circuit, the

lamp BL receives positive current from the battery ET as follows:through wires 4, 56,

60 and 62, front .contact 31, wire 7 3,'through the lamp 'BL to thecommon wire 3. Also, the stick relay K received positive current fromthe battery BT as follows :through wires 4, 56, 60 and 62, front contact32, wires 80 and 101, front contact 14, wire 74, through relay K to thecommon wire 3. With relay K picked up it closes its front contact 38tower T although it is not immediately indicated in tower T That is,when the number of trains in transit between towers T and T exceeds thenumber of horizontal rows of indicators-by one, such indication isstored, so to speak, in the relays A and B The train first in order isnow just west of signals S and S with the train second in order justwest of signal S and the train third in order just west of signal SThird train in 0rdc1*o: Glass A train When the operator notes that thethird train in order is a class A train, he immediately depresses thepush button PA, which completes the circuit for the relay A as follows:from the battery BT, through the wires 84, 85 and 86, through thenormally wires 87 and 88, back contact 12, wire 76, through relay A tothe common wire 3. This energizes relay A through its stick circuit assoon as it closes its front contact 34 with said circuit traced asfollows z-from the battery BT throu h wires 4, 5 and 117, front contact34, wires 7, 88, back contact 12, wire 76, through relay A tov thecommon wire 3. With the relay A held up through its stick circuit backcontact 35 opens the circuit of routing relay R as is obvious from theawing. It will be noted that the breakingfof the energizing circuits ofthe routing relays, has been mentioned last in the list of functionsaccomplished by the class and order relays. This has been done becauseit is necessary that the class and order relays be picked up before therouting relays may drop away in order that the stick circuits of theclass and'order relays may be completed. Toobtain this reopen contact53, wire 82,'front contact 10, I v

sult, the routing relays have been designed to be slow dropping and havebeen designated as slow release relays. The class and order rereleaserelays also, for reasons to be brought out hereinafter.

Uancellati on and transposition of indications As a train passes signalS and S, a'circuit arrangement so functions that, the trainoriginally ofthe first order will cancel the indication representing it, andjwill;transpose the indications representing the followingtrainseachtothenextproceedingorder. is accomplished by having the stickcircuits of the class and order relays A and 13 broken momentarily asthe train passes signals S and S, which sets up a series of successivemovements of the class and order relays cooperating with the routingrelays. When the interlocking plant operator clears the signals S bymeans of lever L, contacts 47 and 48 are closed so that relay IZR isenergized. Now,- when the train of the first order passes signal S thetrack relay T is de-energized opening front contact 40, which breaks thestick circuit of relay A (also 13 if it were energized instead) alsoopening front contact 41 so that the slow-releasing relay IZR drops awayto make contact 42, thus closing the stick circuit of the relay A thesame as if the track relay had again been energized, but

not before the relay A has fully dropped away, opening saidstick'circuit at its stick contact 18. With the relay A in itsde-energized position, the relay R is energized, which opens the circuitof relay B but relay B does not drop away before ithas given a momentaryenergizing impulse to the relay B which picks up said relay so thatfront contact 22 closes its stick circuit. Thus with relay B energized,the relay R again drops away. The de-energizing of relay B picks uprelay R which opens the stick circuit of relay A", but as relay A is aslowreleasing relay, it does not drop away before it has given amomentary energizing impulse to relay A which immediately picks up andremains energized through its stick circuit. With the relay A energized,the relay R is de-energized. As relay R is a slow-releasing relay, ithas remained in an energized position simultaneously with the relay Awhich has completed the energizing circuit for the relay K, thus givingan indication to the interlocking plant operator in tower T that anindication has been given him, which, when acknowledged, will give theoperator in tower T an indication, that he may record anotherapproaching train, as relay R is energized with relay A de-energized.

It will be noted that a momentary depression of push button ER openscontact 52, which has the effect of opening the stick circuits of theclass relays of the first order, with the same resulting effect as thede-energizing of the track relay T in the cancelation of an indication,so that the operator if he so desires may cancel the indication of thefirst order and allow transposition of the remaining indications each,to the next lower order.

There are several major circuits set up dur-' This It should beremembered that under the conditions assumed, the relays A B and A wereup and relays 11 ,11 and B were down; that the signal S was cleared bymovement of lever L toward the right also picking up relay IZR, and thattreading of the first train upon the detector track circuit containingrelay T caused momentary breaking of the stick circuit for relay A thusde-energizing this relay A which in turn effected energization of therelay R With relay A in a de-energized position and with relay R justassuming its energized position, the relay B is deenergized and isdropping away, but as it is slow-releasing, the following circuit ismomentarily made from battery BT through wires 4, 56, 60, 62, frontcontact 30, wires 79, 113, front contact 16, wire 119, through relay Bto the common wire 3; thus picking up relay B and closing the stickcircuit of relay B through front contact 22, and closing front contact23 to light indicator BL The relay R is again de-energized as soon asrelay B is energized.

With relay B in a de-energized position, due to relay R having beenmomentarily energized, this relay B being slow dropping and not havingdropped until after the intervening action of relays B and R and withrelay R in an energized position, due to relay B being de-energized,then relay A is deenergized and is dropping away, but as it is slowreleasing, the following circuit is momentarily made :from battery BTthrough wires 4, 5, and 117, front contact 34, wires 77, 88, frontcontact 12, wires 89, 90, back contact 15, Wire 115, through relay A tothe common Wire 3, thus closing the stick circuit of relay A throughfront contact 26, and closing front contact 27 to light indicator AL Therelay R is again de-energized as soon as the relay A is energized.

With relay A in a de-energized position, due to relay R having beenmomentarily energized the relay R isene'rgized, thus the successiveoperations of the transposition of indications has been completed,leaving the class relays of the third order ready for further storing ofindications.

It will be noted from the above description that as soon as relay R haspicked up, the relay A is immediately energized, which againde-energized the relay R, but before the slow release relay R can dropaway, the relay K is momentarily energized through the following circuit:from battery BT through wires 4, 56, 60, 61, 63, front contact 28,wires 80, 101, front contact 14, wire 74, through relay K to the commonwire 3, thus picking up this relay and closing the stick circuit of saidrelay through its front contact 38, and also closing front contact 39,which gives an indication to the operator of tower T that an indicationrepresenting a train has been given which he has not heretoforeacknowledged. The acknowledgment of this-last indication informs to theoperator in tower T that he now may record another train as soon as itpasses his tower. The pick-up circuit of relay K is so arranged that theabove mentioned momentary energizing impulse is given to said relayonly, when the stored indication is transferred to constitute an activeindication, no matter how many class and order relays there may be.

Summary of transposition of indications With relays A 13 and Aenergized, and u relays R, R and R de-ene'rgized, the indication of thefirst order is cancelled either by- (a Relay A de-energized (circuitopened 9 B'Tl 31,97, 42, 96, 95, 52, 94, 93, 18, 92, A

(b Relay B energized (circuit closed BT1 4, 56, 60, 66, 25, 67, 21, 68,R and 3).

0*) Relay B de-energiz'ed but not dropped for a'time (circuit opened BT4, 56, 60, 62,

30, 79, 113, 16, 114,,B and 3). Y

' Second group (a Relay B energized (circuit closed 40 ET, 4, 56, 50,61, 30, 79, 113, 16, 119, B and 3). (b Relay R de-energized (circuitopened same as under 6 (o Relays B drops in response to deenergizationunder 0 Third group (a) Relay R energized (circuit closed ET, 4, .56,60, 62, 33, 64,29, 65, R and 3). (b Relay A deenergized but not droppedfor atime (circuit opened BT24, 5, 117, 34, 77,

88, 12, 76, A and 3) (o Relay A energized (circuit closed 5 and 3).

Fourth group (a Relay R de-energized (circuit opened 'same'as under (1(6*) Relay. A drops in response to deenergization under b (0*) Relay Renergized (circuit closed BT 4, 5, 6, 7, 37, 3, 35, 9, R" and 3).

The first and third groups each give the position of the relays when thetransposition circuits are closed. The third group also gives theposition of the relays when the indication circuit of the relay K iscompleted for notifying the operator of tower T of the showing of astored indication, while the fourth group gives the final position ofthe relays with two trains still within the approach section and withthe relays of the third order ready for storing another indication. Withthe above mentioned transposition having taken place the relays R", Band A have assumed the energized position.

The class and order relays, except the relays of the first order, musthave a longer releasing period than the routing relays. This isnecessary to eliminate the possibility of (as in the above outlinedexample) the relay B being in a de-energized position, and energizingrelay R before relay R has dropped away, as this would result in theenergization of the relay A, thus giving two indications of the firstorder, which would obviously be very undesirable, making the systemimpractical.

The function of the relay R is to prevent more than one indication ofthe third order tobe stored or to prevent a fourth order in* dication tobe made a third order, by error of operator in remembering the limits ofthe system. It should be understood that certain auxiliary features, andas the audible signals and the acknowledging push buttons and theirfunctions, may be dispensed with, if desired, without departing from theinvention.

Having thus shown and described one specific embodiment of the presentinvention and having described its operating characteristics, it isdesired to be understood that the particular apparatus and circuitarrangements illustrated'have been selected for the purpose ofdescribing the nature of the invention, rather than its scope or thespecific arrangement preferably employed in practicing the invention,that various changes and modifications may be made to adapt theinvention to the particular problem encountered in practicing the same,all without departing from the spirit of the invention or the idea ofmeans underlying the same, except as demanded by the scope of thefollowing claims.

What I claim is 2- 1. A train describing system of the type described,comprising a plurality of indicators positioned so that the location ofan active indicator indicates both the order of an approaching train andthe class of such train, a stick relay for each of said indicators, afront contact for each of said stick relays included in the circuit ofthe corresponding indicator for rendering the indicator active, meansfor energizing a particular stick rela to render a partlcular indicatoractive an means for transposing an indication of a certain order to thenext lower order when the indication of the lowest order is cancelled.

2. A train describing system comprising, a large number of indicatorsarranged in horizontal andvertical rows, in which the particularhorizontal row in which is located an indicator rendered activeindicates the order in which the train it represents is positioned withrespect to other trains on a particular track and in which theparticular vertical row in which such indicator is found signifies theclass to which such train belongs, a stick relay for each of saidindicators, a front contact for each of said stick relays included inthe energizing circuit of the corresponding indicator, and meanseffective when the stick re lay of the first order is de-energized forcaus ing the stick relay of each of the higher orders to be de-energizedand the corresponding stick relay for the next lower order to beenergized.

3. A train describing system comprising, a large number of indicatorsarranged in horizontal and vertical rows, in whichthe particularhorizontal row in which is located an indicator rendered activeindicates the order in which the train it represents is positioned withrespect to other trains on a particular track and in which theparticular vertical row in which such indicator is found signifies theclass to which such train belongs, a stick relay for each of saidindicators, and a supplemental stick relay for each vertical row ofindicators for storing an additional indication, an energizing circuitfor each of said indicators including a front contact of thecorresponding stick relay, and means efiective when a stick relay of thefirst order is .de-energized for de-energizing each of the other stickrelays and effecting energization of the stick relay of the next lowerorder corresponding to each of the de-energized stick relays, so thatcancellation of the indication of the lowest order causes the indicationof each of the higher orders to be transferred to the next lower orderand causes the indication stored in the supplemental stick relay to betransferred to the indication of the highest order.

4. A train descril r of the class described comprising a plurality ofindicators arranged in horizontal and vertical rows, in which thevertical rows designate different classes of trains and in which theparticular indicator of a vertical row indicates the order in which suchtrain is moving with respect to other trains; a stick relay for each ofsaid indicators; a routing relay for each train of the trains that mayapproach in succession; said routing relays being normally energized andthe first routing relay is de -energized upon the entrance of one train,the second routing relay is de-energized upon the entrance of a secondtrain and the third routing relay is deenergized upon the entrance of athird train intoan approach section; circuits for causing the entranceof a train when all of the said routing relays are energized to beregistered in the first horizontal row, to cause the entrance of a trainwhen only the second and third routing relays are energized to cause theindication to be entered into the second horizontal row and to cause theentrance of a train into said approach section when only the thirdrouting relay is energized to register an indication in the thirdhorizontal row of said indicators.

5. A train describing system of the type described, comprising aplurality of indicators wherein each active indicator indicates both theorder of an approaching train and the class of suchtrain, a stick relayfor each of said indicators, a front contact for each of said stickrelays being included in the circuit of the corresponding indicator forrendering the indicator active, means for energizing a particular stickrelay to render a particular indicator active and means forautomatically canceling and transposing an indication of a certain orderto the next lower order when the indication of the first order iscancelled.

6. A train describing system comprising, a large number of indicatorsarranged in horizontal and vertical rows in which the particularhorizontal row in which is located an indicator rendered activeindicates the order in which the train it represents is positioned withrespect to other trains on a particular track and in which theparticular vertical row in which such indicator is found signifies theclass to which such train belongs, a stick relay for each of saidindicators, a front contact for each of said stick relays included inthe energizing circuit of the corresponding indicator, means efiectivewhen the stick 'relay of the first order is de-energized for causing thestick relay of each of the higher orders to be de-energized and thecorresponding stick relay for the next lower order to be energized, andmeans for sounding an alarm for each change of indication.

7. A train describing system comprising, a large number of indicatorsarranged in horizontal and vertical rows, in which the particularhorizontal row in which is located an indicator rendered activeindicates the order in which the train it represents is positioned withrespect to other trains on a particular track and in which theparticular vertical row in which such indicator is found signifies theclass towhich such train belongs,

tion of the indication of the lowest order causes the indication of eachof the higher orders to be transferred to the next lower order andcauses the indication stored in the supplemental stick relay to betransferred to the indication of the highest order.

8. A train describer of the class described comprising a plurality ofindicators arranged in horizontal and vertical rows, in which thevertical rows designate different classes of trains and in which theparticular indicator of a vertical row indicates the order in which suchtrain is moving with respect to other trains; a stick relay for each ofsaid indicators; a routing relay for each train of the trains that mayapproach in succession; said routing relays being normally energized andmanually operable means for causing the first routin relay to bede-energized upon the entrance o one train, the second routing relay tobe cIe-energized upon the entrance of a second train and the thirdrouting relay to be de-energized upon the entrance of a third train intoan approach section; circuits for causing the entrance of a train whenall of the said routing relays are energized to be registered in thefirst horizontal row, to cause the entrance of a train when only thesecond and third routing relays are energized to the indicator active,means for energizing a' particular stick relay to render a particularindicator active, means for transposing an indication of a certain orderto the next lower ting indications from a local to a distant order whenthe, indication of the first order is cancelled, and means for soundingan alarm when a change in the indications occurs.

10. A train describing system for transmittower comprising a largenumber of indicators arranged in horizontal and vertical rows,

the particular indicator rendered active in one of the vertical rowsindicates the order in which the train it represents is positioned withrespect to other trains on a particular track and in which theparticular vertical row in which such indicator is found signifies theclass to which such train belongs, a

stick relay for each of said indicators, a front contact for each ofsaid stick relays included in the energizing circuit of thecorresponding indicator, meansefl'ective when the stick relay of thefirst order is de-energized for causing the stick relay of each of thehigher orders to be de-energized and the corresponding stick relayforthe next lower order to be energized, and means; whereby an operatorat such distant tower may inform an operator at said local tower that achange in indications has been received.

11. A train describing system of the type described, comprising aplurality of indicators positioned so that the location of an activeindicator indicates both the order of an approaching train and the classof such train, a stick relay for each of said indicators, a

front contact for each'of said stick relays included in the circuit ofthe corresponding indicator for rendering the indicator active,means'for energizing a particular stick relay to render a particularindicator active, traffic controlled means for cancelling the indicationof the lowest order, and meansfor transposing an indication-of eachorder to the next lower order respectively when the indication of thelowest order is cancelled.

12. A train describing system comprising, a number of indicatorsarranged in horizontal and vertical rows in which the particularhorizontal row in which an active indicator is located indicates theorder in'which the train it represents is positioned with respect toother trains on a particular track, and in which the particular verticalrow in which such indicator is located indicates the class to which suchtrain belongs, a relay for each of said indicators, a front contact ofeach of said relays included in an energizing clrcuit of thecorresponding indicator, means for deenergizing the relay of the lowestorder, and

means effective upon de-energization of said lowest order relay to shiftthe energizations of each of the other relays to the correspondingrelays of the next lower order.

13. A train describer of the class described comprising, a plurality ofindicators arranged in horizontal and vertical rows in which thevertical rows designate diflt'erent classes of trains and the particularindicator of a vertical row indicates the order in which such train ismoving with respect to other trains, a stick relay for each of saidindicators, a supplemental stick relay for each vertical row ofindicators for storing up an additional indication, arouting relay foreach train of the trains that can approach in succession, said routingrelays being normally energized, and means whereby only the firstrouting relay can be ole-energized upon the entrance of one train, onlythe second routing relay can be de-energized upon the entrance of asecond train if the first routing relay has been de-energized, and onlythe third routing relay can be de-energized upon the entrance of a thirdtrain ifthe second routing relay has been de-energized, circuits forcausing the entrance of a train when all of the routing relays'areenergized to be registered in the first horizontal row of indicators, tocause the entrance of a train when only the second and third routingrelays are energized to be registered in the second horizontal row ofindicators and to cause the entrance of a train when only the thirdrouting relay is energized to store up an indication in the supplementalstick relays.

14. A train describing system of the type described, comprising aplurality of indicators wherein each active indicator indicates both theorder of an approaching train and the class of such train, a relay ateach of said indicators, afront contact of each of said relays beingincluded in the circuit of the corresponding indicator and renderingsuch indicator active, means for energizing a particular relay to renderits indicator active, means for cancelling the indication of the firstorder, and means for automatically transposing each indication to thenext lower order indication when the indication of the first order iscancelled.

15. A train describer of the class in question comprising a plurality ofindicators arranged in horizontal and vertical rows wherein the verticalrow designates the class of a train and the particular indicator of aVertical row indicates the order in which such train is lpositioned withrespect to other trains, a stic relay for each of said indicators, a rowof indication storing relays, a routing relay for each train of thetrains that can approach in succession, said routing relays beinnormally energized, and manually opera 1e means for causing the firstrouting relay to be de-energized upon the entrance of a first train, thesecond routing relay to be de-energized upon the entrance of a secondtrain and the third routing relay to be de-energized upon the entranceof a third train into an approach section, circuits for causing theentrance of a train when all of said routing relays are energized to beregistered in the first horizontal row ofindicators, to cause theentrance of a train when only the second and third routing relays areenergized to be registered in the second horizontal row of indicatorsand to cause the entrance of a train into said approach section whenonly the third routing relay is energized to store an indication in thestoring relays, means for cancelling the indication of the lowest order,and means for transferring each indication to the correspondingindication of the next lower order, and for transferring the storedindication to the corresponding indication of the highest order, whenthe indication of the lowest order is cancelled.

In testimony whereof I aflix my signature.

ANDREW LANGDON.

